Summary

During embryo formation in higher plants, only a rudimentary body forms, consisting of an embryonic root, a stem, and a limited number of leaves. The rest of the plant, including its extensive network of branching roots and stems, is derived from two populations of stem cells at the tips (meristems) of the embryonic root and shoot. The developmental mechanisms that control this branching, however, have been unknown. On page 1306 of this issue, Moreno-Risueno et al. (1) demonstrate that cyclic expression of genes in root meristems can generate the elaborate network of branching roots that anchors the plant and provides it with essential nutrients.